On Thu, Sep 28, 2017 at 10:29:55AM +0200, Ingo Molnar wrote: > > * Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> wrote: > > > For boot-time switching between paging modes, we need to be able to > > change STACK_TOP_MAX at runtime. > > > > The change is trivial and it doesn't affect kernel image size. > > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > > --- > > arch/x86/include/asm/processor.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h > > index 3fa26a61eabc..fa9300ccce1b 100644 > > --- a/arch/x86/include/asm/processor.h > > +++ b/arch/x86/include/asm/processor.h > > @@ -871,7 +871,7 @@ static inline void spin_lock_prefetch(const void *x) > > IA32_PAGE_OFFSET : TASK_SIZE_MAX) > > > > #define STACK_TOP TASK_SIZE_LOW > > -#define STACK_TOP_MAX TASK_SIZE_MAX > > +#define STACK_TOP_MAX (pgtable_l5_enabled ? TASK_SIZE_MAX : DEFAULT_MAP_WINDOW) > > While it's only used once in fs/exec.c, why doesn't it affect kernel image size? Oh. After closer look the patch is redundant. The STACK_TOP_MAX is already dynamic due to dynamic TASK_SIZE_MAX, so gcc generates exactly the same code before and after the patch. I'll drop it. -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
